CN117042562A

CN117042562A - Organic vapor jet printing system

Info

Publication number: CN117042562A
Application number: CN202310520481.8A
Authority: CN
Inventors: S·S·奥奇; V·博古斯拉夫斯基; E·埃尔南德斯; K·K·阮; M·菲利皮; 马修·金; D·托特
Original assignee: Universal Display Corp
Current assignee: Universal Display Corp
Priority date: 2022-05-09
Filing date: 2023-05-09
Publication date: 2023-11-10

Abstract

The present application relates to an organic vapor jet printing system. An organic vapor jet printing OVJP device is provided that includes an OVJP print die having one or more transport channels to transport organic material and carrier gas to an area under the print die and having one or more exhaust channels to remove material from under the print die. A directly heated transfer line connected to the one or more transfer channels and a source of the organic material external to the OVJP printed die includes a resistive material and a plurality of electrical connections to the resistive material. When an electrical current is applied to the resistive material via the plurality of electrical connections, the resistive material heats the interior of the directly heated transfer line.

Description

Organic vapor jet printing system

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application Ser. No. 63/339,839, filed 5/9 of 2022, the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to an apparatus and technique for manufacturing an organic light emitting device, such as an organic light emitting diode, and an apparatus and technique including an organic light emitting device.

Background

Optoelectronic devices utilizing organic materials are becoming increasingly popular for a number of reasons. Many of the materials used to fabricate the devices are relatively inexpensive, so organic photovoltaic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials (e.g., their flexibility) may make them more suitable for specific applications, such as fabrication on flexible substrates. Examples of organic optoelectronic devices include organic light emitting diodes/devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can have performance advantages over conventional materials. For example, the wavelength at which the organic emissive layer emits light can generally be readily tuned with appropriate dopants.

OLEDs utilize organic thin films that emit light when a voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, lighting and backlighting. Several OLED materials and configurations are described in U.S. patent nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

One application of phosphorescent emissive molecules is in full color displays. Industry standards for such displays require pixels adapted to emit a particular color (referred to as a "saturated" color). In particular, these standards require saturated red, green and blue pixels. Alternatively, the OLED may be designed to emit white light. In conventional liquid crystal displays, the emission from a white backlight is filtered using an absorbing filter to produce red, green and blue emissions. The same technique can also be used for OLEDs. The white OLED may be a single EML device or a stacked structure. The color may be measured using CIE coordinates well known in the art.

As used herein, the term "organic" encompasses polymeric materials and small molecule organic materials that may be used to fabricate organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and may be substantial in nature. In some cases, the small molecule may comprise repeat units. For example, the use of long chain alkyl groups as substituents does not remove the molecule from the "small molecule" class. Small molecules may also be incorporated into the polymer, for example as side groups on the polymer backbone or as part of the backbone. Small molecules can also serve as the core of a dendrimer, which consists of a series of chemical shells built on the core. The core moiety of the dendrimer may be a fluorescent or phosphorescent small molecule emitter. Dendrimers may be "small molecules" and all dendrimers currently used in the OLED field are considered small molecules.

As used herein, "top" means furthest from the substrate, while "bottom" means closest to the substrate. Where a first layer is described as being "disposed" over "a second layer, the first layer is disposed farther from the substrate. Unless a first layer is "in contact with" a second layer, other layers may be present between the first and second layers. For example, a cathode may be described as "disposed over" an anode even though various organic layers are present between the cathode and the anode.

As used herein, "solution processable" means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium in the form of a solution or suspension.

A ligand may be referred to as "photosensitive" when it is believed that the ligand contributes directly to the photosensitive properties of the emissive material. When the ligand is considered not to contribute to the photosensitive properties of the emissive material, the ligand may be referred to as "ancillary", but the ancillary ligand may alter the properties of the photosensitive ligand.

As used herein, and as will be generally understood by those of skill in the art, if the first energy level is closer to the vacuum energy level, then the first "highest occupied molecular orbital" (Highest Occupied Molecular Orbital, HOMO) or "lowest unoccupied molecular orbital" (Lowest Unoccupied Molecular Orbital, LUMO) energy level is "greater than" or "higher than" the second HOMO or LUMO energy level. Since Ionization Potential (IP) is measured as a negative energy relative to the vacuum level, a higher HOMO level corresponds to an IP with a smaller absolute value (less negative). Similarly, a higher LUMO energy level corresponds to an Electron Affinity (EA) with a smaller absolute value (less negative EA). On a conventional energy level diagram with vacuum energy level on top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. The "higher" HOMO or LUMO energy level appears closer to the top of this figure than the "lower" HOMO or LUMO energy level.

As used herein, and as will be generally understood by those of skill in the art, a first work function is "greater than" or "higher than" a second work function if the first work function has a higher absolute value. Since work function is typically measured as a negative number relative to the vacuum level, this means that the "higher" work function is more negative (more negative). On a conventional energy level diagram with the vacuum energy level on top, a "higher" work function is illustrated as being farther from the vacuum energy level in a downward direction. Thus, the definition of HOMO and LUMO energy levels follows a different rule than work function.

Layers, materials, regions and colors of light emitted by the device may be described herein with reference to them. In general, as used herein, an emissive region described as generating a particular color of light may include one or more emissive layers disposed on each other in a stacked manner.

As used herein, a "red" layer, material, region, or device refers to a layer, material, region, or device that emits light in the range of about 580-700nm or whose emission spectrum has the highest peak in that region. Similarly, a "green" layer, material, region or device refers to a layer, material, region or device that emits or has an emission spectrum with a peak wavelength in the range of about 500-600 nm; "blue" layer, material or device refers to a layer, material or device that emits or has an emission spectrum with a peak wavelength in the range of about 400-500 nm; and a "yellow" layer, material, region or device refers to a layer, material, region or device having an emission spectrum with a peak wavelength in the range of about 540-600 nm. In some arrangements, individual regions, layers, materials, regions, or devices may provide individual "deep blue" and "light blue" light. As used herein, in an arrangement that provides separate "light blue" and "dark blue" components, a "dark blue" component refers to a component having a peak emission wavelength that is at least about 4nm less than the peak emission wavelength of the "light blue" component. Typically, the peak emission wavelength of the "light blue" component is in the range of about 465nm to 500nm, and the peak emission wavelength of the "deep blue" component is in the range of about 400nm to 470nm, although these ranges may vary for some configurations. Similarly, a color changing layer refers to a layer that converts or modifies light of another color into light having a wavelength specified for that color. For example, a "red" color filter refers to a color filter that forms light having a wavelength in the range of about 580-700 nm. In general, there are two types of color changing layers: a color filter to modify the spectrum by removing unwanted wavelengths of light, and a color changing layer to convert higher energy photons to lower energy. "color" component refers to a component that, when activated or in use, generates or otherwise emits light having a particular color as previously described. For example, "a first emission region of a first color" and "a second emission region of a second color different from the first color" describe two emission regions that emit two different colors as previously described when activated within a device.

As used herein, emissive materials, layers, and regions may be distinguished from one another and from other structures based on light originally generated by the materials, layers, or regions, rather than light ultimately emitted by the same or different structures. Initial light generation is typically the result of a change in energy level that results in photon emission. For example, an organic emissive material may initially produce blue light, which may be converted to red or green light by a color filter, quantum dot, or other structure, such that the complete emissive stack or subpixel emits red or green light. In this case, the initial emissive material or layer may be referred to as the "blue" component, even though the subpixels are of the "red" or "green" components.

In some cases, it may be preferable to describe the color of components, such as the color of the emission area, sub-pixels, color changing layers, etc., according to 1931CIE coordinates. For example, the yellow emissive material may have multiple peak emission wavelengths, one in or near the edge of the "green" region, and one within or near the edge of the "red" region, as previously described. Thus, as used herein, each color item also corresponds to a shape in the 1931CIE coordinate color space. The shape in the 1931CIE color space is constructed by following a trajectory between two color points and any other internal points. For example, the internal shape parameters of red, green, blue, and yellow may be defined as follows:

Further details regarding OLEDs and the definitions described above can be found in U.S. patent No. 7,279,704, which is incorporated herein by reference in its entirety.

Disclosure of Invention

According to one embodiment, an organic light emitting diode/device (OLED) is also provided. An OLED may include an anode, a cathode, and an organic layer disposed between the anode and the cathode. According to one embodiment, the organic light emitting device is incorporated into one or more devices selected from consumer products, electronic component modules, and/or lighting panels.

There is provided an Organic Vapor Jet Printing (OVJP) apparatus comprising: an OVJP print die comprising one or more transport channels to transport organic material and carrier gas to an area under the print die; and a directly heated transfer line connected to the one or more transfer channels and configured to be connected to a source of organic material external to the OVJP printed die, wherein the directly heated transfer line includes a resistive material and a plurality of electrical connections to the resistive material, wherein the resistive material heats an interior of the directly heated transfer line when an electrical current is applied to the resistive material via the plurality of electrical connections. The die may include one or more exhaust channels disposed, for example, on one or both sides of each transport channel.

The directly heated transfer line may have a constant cross-sectional shape and area. Which may be formed entirely or substantially entirely of the resistive material. The end of the directly heated transfer line connected to the OVJP printed die line may be electrically insulated from the OVJP printed die. The directly heated transfer line may be formed in a spiral, S-shape or L-shape.

The heat shield may be disposed about the directly heated transfer line. The heat shield may include a ceramic housing with sufficient clearance to allow movement of the directly heated transfer line when the OVJP device moves between a maximum horizontal displacement and a minimum horizontal displacement. The heat shield may include a conduit disposed about the directly heated transfer line, the conduit having a constant cross-sectional shape and area. The active cooler may be arranged and configured to cool at least a portion of the conduit.

The OVJP device may comprise: one or more temperature sensors; and a processor in signal communication with the one or more temperature sensors and configured to perform closed loop control of the temperature within the directly heated transfer line based on the temperature signals provided by the one or more temperature sensors.

The OVJP device may include a directly heated exhaust line connected to one or more exhaust channels in the printed die and configured to be connected to an external source of vacuum, wherein the directly heated exhaust line includes: a resistive material; and a plurality of electrical connections to the resistive material, wherein the resistive material of the directly heated exhaust line heats an interior of the directly heated exhaust line when an electrical current is applied to the resistive material of the directly heated exhaust line via the plurality of electrical connections of the directly heated exhaust line. The directly heated exhaust line may be disposed within a heat shield conduit having a constant cross-sectional shape and area. The active cooler may be arranged and configured to cool at least a portion of the piping surrounding the exhaust line.

OVJP devices may include a manifold configured to distribute material from a flexible conduit to one or more delivery channels, which may be composed of, for example, alN, al ₂ O ₃ And Si (Si) ₃ N ₄ Is formed of the material of (a). The manifold may be formed of a material such as W, mo, alN, single crystal Si, poly Si, columnar Si, or a combination thereof.

One or more temperature sensors may be attached to the manifold, and a processor in signal communication with the temperature sensors may be configured to perform closed loop control of the temperature within the manifold and/or within the directly heated transfer line.

The OVJP printheads as disclosed may incorporate one or more print dies having nozzles that deliver hot organic gas to and from the substrate. The print head may include one or more print dies and/or manifold structures that distribute hot organic gases to the dies and/or direct residual gases away from the dies in a uniform manner. The printed die may be hermetically sealed to the manifold structure, such as by clamping/sealing, high temperature bonding (e.g., soldering, frit), etc. The manifold may be formed of a material having a coefficient of thermal expansion that approximates the coefficient of thermal expansion of the printed die.

The OVJP printhead may contain a heater that allows tight control of the gas temperature as it reaches and leaves the substrate. The heater may be embedded in, attached to, or patterned onto the printhead manifold, and may include different zones, each with a sensor for closed loop control.

OVJP printheads may include mechanisms that allow for controlled and/or symmetrical expansion about their thermal centers. Which may include flexures, low friction surfaces, and the like.

The OVJP printhead may include an active closed loop flight control mechanism that may include a sensor configured to measure the flight height between the printhead and the substrate and an actuator to control this gap to the left and right of the die.

The OVJP printhead may be air tight interfaced with hot gas supply and exhaust lines. The gas lines may be attached to the OVJP print head by clamping/sealing, bonding to flanges, etc. The flange material may have a coefficient of thermal expansion that is close to the coefficient of thermal expansion of the print head and may accommodate vertical movement of the print head.

The OVJP printheads may include a heat shield that protects the rest of the system from high temperatures in the manifold and/or other components (e.g., organic material sources, transfer lines, exhaust lines, etc.). The heat shield may comprise an active cooling shield, a thermally insulating material, a vacuum shield, or the like. The heat shield may include a plurality of sections including a front, a rear, sides, a top, components dedicated to protecting the fly-height sensor, components for protecting the vertical motion actuator, and combinations thereof. The cold plate at the bottom of the print head can mitigate the increase in substrate temperature and the resulting deformation caused by the hot die and gas.

Drawings

Fig. 1 shows an organic light emitting device.

Fig. 2 shows an inverted organic light emitting device without a separate electron transport layer.

Fig. 3 shows an example OVJP system as disclosed herein.

Fig. 4A shows an example of a directly heated delivery line as disclosed herein.

Fig. 4B shows an enlarged view of the proximal ends of the print manifold, printheads, and transfer lines shown in fig. 4A.

Fig. 4C shows an example of a transfer line, exhaust line, and printhead including various insulating structures as disclosed herein.

Fig. 4D shows an example of a heat shield in the form of a tube disposed about a transfer line as disclosed herein.

Fig. 4E shows an example of a heat shield in the form of an insulated housing as disclosed herein.

Fig. 5 shows an example of a three-dimensional helical portion of a tube in a transfer line as disclosed herein.

Fig. 6 shows an example of an S-shaped transfer line and an arrangement with multiple transfer lines as disclosed herein.

Detailed Description

In general, an OLED includes at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer. The injected holes and electrons each migrate toward the oppositely charged electrode. When an electron and a hole are localized on the same molecule, an "exciton" is formed, which is a localized electron-hole pair having an excited energy state. Light is emitted when the exciton relaxes through a light emission mechanism. In some cases, excitons may be localized on an excimer or exciplex. Non-radiative mechanisms (such as thermal relaxation) may also occur, but are generally considered undesirable.

Initial OLEDs used emissive molecules that emitted light ("fluorescence") from a singlet state, as disclosed, for example, in U.S. patent No. 4,769,292, which is incorporated by reference in its entirety. Fluorescence emission typically occurs in time frames less than 10 nanoseconds.

Recently, OLEDs have been demonstrated that have emissive materials that emit light from a triplet state ("phosphorescence"). Baldo et al, "efficient phosphorescent emission from organic electroluminescent devices (Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices)", nature, vol.395, 151-154,1998 ("Baldo-I"); and Bardo et al, "Very efficient green organic light emitting device based on electrophosphorescence (Very high-efficiency green organic light-emitting devices based on electrophosphorescence)", applied physical fast report (appl. Phys. Lett.), vol.75, stages 3,4-6 (1999) ("Bardo-II"), incorporated by reference in its entirety. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704, columns 5-6, which is incorporated by reference.

Fig. 1 shows an organic light emitting device 100. The figures are not necessarily drawn to scale. The device 100 may include a substrate 110, an anode 115, a hole injection layer 120, a hole transport layer 125, an electron barrier layer 130, an emissive layer 135, a hole barrier layer 140, an electron transport layer 145, an electron injection layer 150, a protective layer 155, a cathode 160, and a barrier layer 170. Cathode 160 is a composite cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 may be fabricated by depositing the layers in sequence. The nature and function of these various layers and example materials are described in more detail in U.S. Pat. No. 7,279,704 at columns 6-10, which is incorporated by reference.

Further examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. patent No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is doped with F in a 50:1 molar ratio ₄ m-MTDATA of TCNQ, as disclosed in U.S. patent application publication No. 2003/0239980, which is incorporated by reference in its entirety. Examples of emissive and host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al, which is incorporated by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a molar ratio of 1:1, as disclosed in U.S. patent application publication No. 2003/0230980, which is incorporated by reference in its entirety. Examples of cathodes comprising composite cathodes having a thin layer of metal (e.g., mg: ag) containing an overlying transparent, conductive, sputter-deposited ITO layer are disclosed in U.S. patent nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety. The theory and use of barrier layers is described in more detail in U.S. patent No. 6,097,147 and U.S. patent application publication No. 2003/0230980, which are incorporated by reference in their entirety. Examples of implanted layers are provided in U.S. patent application publication No. 2004/0174116, which is incorporated by reference in its entirety. A description of protective layers can be found in U.S. patent application publication No. 2004/0174116, which is incorporated by reference in its entirety. The barrier layer 170 may be a single layer or a multi-layer barrier and may cover or enclose other layers of the device. The barrier layer 170 may also surround the substrate 110 and/or it may be disposed between the substrate and other layers of the device. The barrier may also be referred to as an encapsulant, encapsulation layer, protective layer, or permeation barrier, and generally provides other layers that prevent moisture, ambient air, and other similar materials from penetrating the device Is a protection of (a). Examples of barrier layer materials and structures are provided in U.S. patent nos. 6,537,688, 6,597,111, 6,664,137, 6,835,950, 6,888,305, 6,888,307, 6,897,474, 7,187,119, and 7,683,534, each of which is incorporated by reference in its entirety.

Fig. 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, an emissive layer 220, a hole transport layer 225, and an anode 230. The device 200 may be fabricated by depositing the layers in sequence. Because the most common OLED configuration has a cathode disposed above an anode, and the device 200 has a cathode 215 disposed below an anode 230, the device 200 may be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 may be used in the corresponding layers of device 200. Fig. 2 provides one example of how some layers may be omitted from the structure of the apparatus 100.

The simple layered structure illustrated in fig. 1 and 2 is provided by way of non-limiting example, and it should be understood that embodiments of the present invention may be used in conjunction with a variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. Functional OLEDs may be obtained by combining the various layers described in different ways, or the layers may be omitted entirely based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe the various layers as comprising a single material, it should be understood that combinations of materials may be used, such as mixtures of host and dopant, or more generally, mixtures. Further, the layers may have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports holes and injects holes into emissive layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. This organic layer may comprise a single layer, or may further comprise multiple layers of different organic materials as described, for example, with respect to fig. 1 and 2.

Structures and materials not specifically described, such as OLEDs (PLEDs) comprising polymeric materials, such as disclosed in frank (Friend) et al, U.S. patent No. 5,247,190, which is incorporated by reference in its entirety, may also be used. By way of another example, an OLED with a single organic layer may be used. The OLEDs can be stacked, for example, as described in U.S. patent No. 5,707,745 to Forrest et al, which is incorporated by reference in its entirety. The OLED structure may deviate from the simple layered structure illustrated in fig. 1 and 2. For example, the substrate may include an angled reflective surface to improve out-coupling, such as a mesa structure as described in U.S. Pat. No. 6,091,195 to Furster et al, and/or a pit structure as described in U.S. Pat. No. 5,834,893 to Boolean et al, which are incorporated by reference in their entirety.

In some embodiments disclosed herein, an emissive layer or material (e.g., emissive layer 135 and emissive layer 220, respectively, shown in fig. 1-2) may comprise quantum dots. Unless indicated to the contrary or otherwise as the case may be, as understood by those of skill in the art, an "emissive layer" or "emissive material" as disclosed herein may comprise an organic emissive material and/or an emissive material comprising quantum dots or equivalent structures. In general, the emissive layer comprises an emissive material within a host matrix. Such an emissive layer may comprise only quantum dot materials that convert light emitted by the individual emissive material or other emitter, or it may also comprise individual emissive materials or other emitters, or it may itself emit light directly by application of an electrical current. Similarly, a color changing layer, color filter, up-conversion or down-conversion layer or structure may comprise a material containing quantum dots, but such layers are not considered "emissive layers" as disclosed herein. In general, an "emissive layer" or material is a material that emits an initial light based on injected charge, where the initial light may be altered by another layer, such as a color filter or other color altering layer, that does not itself emit the initial light within the device, but may re-emit altered light having a different spectral content based on absorbing the initial light emitted by the emissive layer and down-converting to a lower energy light emission. In some embodiments disclosed herein, the color changing layer, color filter, up-conversion and/or down-conversion layer may be disposed external to the OLED device, for example, above or below the electrodes of the OLED device.

Any of the layers of the various embodiments may be deposited by any suitable method unless otherwise specified. Preferred methods for the organic layer include thermal evaporation, ink jet (as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, incorporated by reference in their entirety), organic vapor deposition (OVPD) (as described in U.S. Pat. No. 6,337,102, incorporated by reference in its entirety), and deposition by Organic Vapor Jet Printing (OVJP) (as described in U.S. Pat. No. 7,431,968, incorporated by reference in its entirety). Other suitable deposition methods include spin-coating and other solution-based processes. The solution-based process is preferably carried out under nitrogen or an inert atmosphere. For other layers, the preferred method involves thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding (as described in U.S. patent nos. 6,294,398 and 6,468,819, incorporated by reference in their entirety), and patterning associated with some of the deposition methods, such as inkjet and OVJD. Other methods may also be used. The material to be deposited may be modified to suit the particular deposition method. For example, substituents such as alkyl and aryl groups that are branched or unbranched and preferably contain at least 3 carbons can be used in small molecules to enhance their ability to withstand solution processing. Substituents having 20 carbons or more may be used, and 3 to 20 carbons are a preferred range. A material with an asymmetric structure may have better solution processibility than a material with a symmetric structure because an asymmetric material may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.

Devices fabricated according to embodiments of the present invention may further optionally include barrier layers. One purpose of the barrier layer is to protect the electrodes and the organic layer from harmful substances exposed to the environment containing moisture, vapors and/or gases, etc. The barrier layer may be deposited on the substrate, electrode, under or beside the substrate, electrode, or on any other portion of the device, including the edge. The barrier layer may comprise a single layer or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may comprise a composition having a single phase and a composition having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic compound or an organic compound or both. Preferred barrier layers include mixtures of polymeric and non-polymeric materials, as described in U.S. patent No. 7,968,146, PCT patent application No. PCT/US2007/023098, and PCT/US2009/042829, which are incorporated herein by reference in their entirety. To be considered as a "mixture", the aforementioned polymeric and non-polymeric materials that make up the barrier layer should be deposited under the same reaction conditions and/or simultaneously. The weight ratio of polymeric material to non-polymeric material may be in the range of 95:5 to 5:95. The polymeric material and the non-polymeric material may be produced from the same precursor material. In one example, the mixture of polymeric and non-polymeric materials consists essentially of polymeric silicon and inorganic silicon.

In some embodiments, at least one of the anode, cathode, or new layer disposed over the organic emissive layer is used as the enhancement layer. The enhancement layer includes a plasmonic material exhibiting surface plasmon resonance, the plasmonic material non-radiatively coupled to the emitter material and transferring excited state energy from the emitter material to a non-radiative mode of surface plasmon polaritons. The enhancement layer is provided at a threshold distance from the organic emissive layer that is no more than a total non-radiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer, and the threshold distance is a distance where the total non-radiative decay rate constant is equal to the total radiative decay rate constant. In some embodiments, the OLED further comprises an outcoupling layer. In some embodiments, the outcoupling layer is disposed over the enhancement layer on an opposite side of the organic emissive layer. In some embodiments, the outcoupling layer is disposed on the opposite side of the emissive layer from the enhancement layer, but still allows energy to be outcoupled from the surface plasmon mode of the enhancement layer. The outcoupling layer scatters energy from the surface plasmon polaritons. In some embodiments, this energy is scattered into free space in the form of photons. In other embodiments, energy is scattered from surface plasmon modes of the device into other modes, such as, but not limited to, an organic waveguide mode, a substrate mode, or another waveguide mode. If the energy is scattered into the non-free space mode of the OLED, other outcoupling schemes may be incorporated to extract the energy into free space. In some embodiments, one or more intervening layers may be disposed between the enhancement layer and the outcoupling layer. Examples of intervening layers may be dielectric materials, including organic, inorganic, perovskite, oxide, and may include stacks and/or mixtures of these materials.

The enhancement layer modifies the effective properties of the medium in which the emitter material resides, causing any or all of the following: reduced emissivity, modification of emission line shape, variation of emission intensity and angle, variation of stability of the emitter material, variation of efficiency of the OLED, and reduction of efficiency decay of the OLED device. Placing the enhancement layer on the cathode side, the anode side, or both sides creates an OLED device that takes advantage of any of the effects described above. In addition to the specific functional layers mentioned herein and illustrated in the various OLED examples shown in the figures, an OLED according to the present disclosure may also include any of the other functional layers commonly found in OLEDs.

The enhancement layer may be composed of a plasmonic material, an optically active metamaterial or a hyperbolic metamaterial. As used herein, plasmonic materials are materials in which the real part of the dielectric constant crosses zero in the visible or ultraviolet region of the electromagnetic spectrum. In some embodiments, the plasmonic material comprises at least one metal. In such embodiments, the metal may comprise at least one of: ag. Al, au, ir, pt, ni, cu, W, ta, fe, cr, mg, ga, rh, ti, ru, pd, in, bi, ca, alloys or mixtures of these materials, and stacks of these materials. In general, metamaterials are media composed of different materials, where the media as a whole acts differently than the sum of its material portions. Specifically, we define an optically active metamaterial as a material having both negative permittivity and negative permeability. On the other hand, hyperbolic metamaterials are anisotropic media in which the permittivity or permeability has different signs for different spatial directions. Optically active metamaterials and hyperbolic metamaterials are strictly distinguished from many other photonic structures, such as distributed bragg reflectors (Distributed Bragg Reflector, "DBRs"), because the medium should exhibit uniformity in the direction of propagation over the length scale of the wavelength of light. Using terms that will be understood by those skilled in the art: the dielectric constant of a metamaterial in the direction of propagation can be approximately described by an effective medium. Plasmonic materials and metamaterials provide a means of controlling light propagation that can enhance OLED performance in a variety of ways.

In some embodiments, the enhancement layer is provided as a planar layer. In other embodiments, the enhancement layer has wavelength-sized features that are periodically, quasi-periodically, or randomly arranged, or sub-wavelength-sized features that are periodically, quasi-periodically, or randomly arranged. In some embodiments, the wavelength-sized features and the sub-wavelength-sized features have sharp edges.

In some embodiments, the outcoupling layer has a periodically, quasi-periodically, or randomly arranged wavelength-sized feature, or has a periodically, quasi-periodically, or randomly arranged sub-wavelength-sized feature. In some embodiments, the outcoupling layer may be composed of a plurality of nanoparticles, and in other embodiments, the outcoupling layer is composed of a plurality of nanoparticles disposed on a material. In these embodiments, the outcoupling may be tuned by at least one of: changing the size of the plurality of nanoparticles, changing the shape of the plurality of nanoparticles, changing the material of the plurality of nanoparticles, adjusting the thickness of the material, changing the refractive index of the material or an additional layer disposed on the plurality of nanoparticles, changing the thickness of the reinforcing layer, and/or changing the material of the reinforcing layer. The plurality of nanoparticles of the device may be formed from at least one of: a metal, a dielectric material, a semiconductor material, a metal alloy, a mixture of dielectric materials, a stack or layering of one or more materials, and/or a core of one type of material, and the core is coated with a shell of a different type of material. In some embodiments, the outcoupling layer is composed of at least metal nanoparticles, wherein the metal is selected from the group consisting of: ag. Al, au, ir, pt, ni, cu, W, ta, fe, cr, mg, ga, rh, ti, ru, pd, in, bi, ca, alloys or mixtures of these materials, and stacks of these materials. The plurality of nanoparticles may have additional layers disposed over them. In some embodiments, the polarization of the emission may be tuned using an outcoupling layer. Changing the dimensions and periodicity of the outcoupling layer may select a class of polarizations that preferentially outcouple to air. In some embodiments, the outcoupling layer also serves as an electrode of the device.

It is believed that the Internal Quantum Efficiency (IQE) of fluorescent OLEDs can be limited by spin statistics that delay fluorescence by more than 25%. As used herein, there are two types of delayed fluorescence, namely P-type delayed fluorescence and E-type delayed fluorescence. The P-type delayed fluorescence is generated by triplet-triplet annihilation (TTA).

On the other hand, the E-type delayed fluorescence does not depend on the collision of two triplet states, but on the number of thermal population between triplet and singlet excited states. Compounds capable of generating E-type delayed fluorescence are needed to have very small singlet-triplet gaps. The thermal energy may activate a transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as Thermally Activated Delayed Fluorescence (TADF). One significant feature of TADF is that the delay component increases with increasing temperature due to increasing thermal energy. The fraction of backfill singlet excited states may reach 75% if the rate of intersystem crossing is sufficiently fast to minimize non-radiative decay from the triplet states. The total singlet fraction may be 100%, well beyond the spin statistical limit of the electrically generated excitons.

Type E delayed fluorescence features can be found in excitation complex systems or in single compounds. Without being bound by theory, it is believed that the E-delayed fluorescence requires that the luminescent material have a small singlet-triplet energy gap (Δes-T). Organic, metal-free donor-acceptor luminescent materials may be able to achieve this. The emission of these materials is generally characterized by a donor-acceptor Charge Transfer (CT) type emission. The spatial separation of HOMO from LUMO in these donor-acceptor type compounds generally results in a small Δes-T. These states may relate to CT states. Typically, donor-acceptor luminescent materials are constructed by linking an electron donor moiety (e.g., an amino or carbazole derivative) to an electron acceptor moiety (e.g., containing an N six-membered aromatic ring).

Devices manufactured in accordance with embodiments of the present invention may be incorporated into a wide variety of electronic component modules (or units), which may be incorporated into a wide variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices (e.g., discrete light source devices or lighting panels), etc., that may be utilized by end user product manufacturers. The electronics assembly module may optionally contain drive electronics and/or a power source. Devices manufactured in accordance with embodiments of the present invention may be incorporated into a wide variety of consumer products having one or more electronic component modules (or units) incorporated therein. Disclosed is a consumer product comprising an OLED comprising a compound of the present disclosure in an organic layer in the OLED. The consumer product should include any kind of product that contains one or more light sources and/or one or more of a certain type of visual display. Some examples of such consumer products include flat panel displays, curved displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, rollable displays, foldable displays, stretchable displays, laser printers, telephones, cellular telephones, tablet computers, tablet phones, personal Digital Assistants (PDAs), wearable devices, laptop computers, digital cameras, video cameras, viewfinders, micro-displays with a diagonal of less than 2 inches, 3D displays, virtual reality or augmented reality displays, vehicles, video walls including a plurality of tiled displays, theatre or gym screens, and signs. Various control mechanisms may be used to control devices made in accordance with the present invention, including passive matrices and active matrices. Many of the devices are intended to be used in a temperature range that is comfortable for humans, such as 18 ℃ to 30 ℃, and more preferably at room temperature (20 ℃ to 25 ℃), but can be used outside this temperature range (e.g. -40 ℃ to 80 ℃).

The materials and structures described herein may be applied in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may employ the materials and structures. More generally, organic devices such as organic transistors may employ the materials and structures.

In some embodiments, the OLED has one or more features selected from the group consisting of: flexible, crimpable, collapsible, stretchable and bendable. In some embodiments, the OLED is transparent or translucent. In some embodiments, the OLED further comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED includes an RGB pixel arrangement or a white plus color filter pixel arrangement. In some embodiments, the OLED is a mobile device, a handheld device, or a wearable device. In some embodiments, the OLED is a display panel having a diagonal of less than 10 inches or an area of less than 50 square inches. In some embodiments, the OLED is a display panel having a diagonal of at least 10 inches or an area of at least 50 square inches. In some embodiments, the OLED is an illumination panel.

In some embodiments of the emission area, the emission area further comprises a body.

In some embodiments, the compound may be an emissive dopant. In some embodiments, the compound may produce emission via phosphorescence, fluorescence, thermally activated delayed fluorescence (i.e., TADF, also known as delayed fluorescence of type E), triplet-triplet annihilation, or a combination of these processes.

The OLEDs disclosed herein can be incorporated into one or more of consumer products, electronics assembly modules, and lighting panels. The organic layer may be an emissive layer, and the compound may be an emissive dopant in some embodiments, and the compound may be a non-emissive dopant in other embodiments.

The organic layer may further comprise a host. In some embodiments, two or more bodies are preferred. In some embodiments, the host used may be a) bipolar, b) electron transport, c) hole transport, or d) a wide bandgap material that plays a small role in charge transport. In some embodiments, the host may comprise a metal complex. The host may be an inorganic compound.

In combination with other materials

Materials described herein as suitable for use in particular layers in an organic light emitting device may be used in combination with a variety of other materials present in the device. For example, the emissive dopants disclosed herein can be used in combination with a wide variety of hosts, transport layers, barrier layers, implant layers, electrodes, and other layers that may be present. The materials described or mentioned below are non-limiting examples of materials that may be used in combination with the compounds disclosed herein, and one of ordinary skill in the art may readily review the literature to identify other materials that may be used in combination.

The various emissive and non-emissive layers and arrangements disclosed herein may use different materials. Examples of suitable materials are disclosed in U.S. patent application publication No. 2017/0229663, which disclosure is incorporated by reference in its entirety.

Conductive dopants:

the charge transport layer may be doped with a conductive dopant to substantially change its charge carrier density, which in turn will change its conductivity. Conductivity is increased by the generation of charge carriers in the host material and, depending on the type of dopant, a change in Fermi level (Fermi level) of the semiconductor can also be achieved. The hole transport layer may be doped with a p-type conductivity dopant, and an n-type conductivity dopant is used in the electron transport layer.

HIL/HTL：

The hole injection/transport material used in the present invention is not particularly limited, and any compound may be used as long as the compound is generally used as a hole injection/transport material.

EBL：

An Electron Blocking Layer (EBL) may be used to reduce the number of electrons and/or excitons that leave the emissive layer. The presence of such a barrier layer in a device may result in substantially higher efficiency and/or longer lifetime than a similar device lacking such a barrier layer. Furthermore, a blocking layer may be used to limit the emission to a desired area of the OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to vacuum level) and/or higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in the EBL contains the same molecule or the same functional group as used in one of the hosts described below.

A main body:

the light-emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as a light-emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complex or organic compound may be used as long as the triplet energy of the host is greater than that of the dopant. Any host material may be used with any dopant so long as the triplet criteria are met.

HBL：

A Hole Blocking Layer (HBL) may be used to reduce the number of holes and/or excitons that leave the emissive layer. The presence of such a barrier layer in a device may result in substantially higher efficiency and/or longer lifetime than a similar device lacking the barrier layer. Furthermore, a blocking layer may be used to limit the emission to a desired area of the OLED. In some embodiments, the HBL material has a lower HOMO (farther from the vacuum level) and/or higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (farther from the vacuum level) and/or higher triplet energy than one or more of the hosts closest to the HBL interface.

ETL：

An Electron Transport Layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping may be used to enhance conductivity. Examples of the ETL material are not particularly limited, and any metal complex or organic compound may be used as long as it is generally used to transport electrons.

Charge Generation Layer (CGL)

In tandem or stacked OLEDs, CGL plays a fundamental role in performance, consisting of n-doped and p-doped layers for injecting electrons and holes, respectively. Electrons and holes are supplied by the CGL and the electrode. Electrons and holes consumed in the CGL are refilled with electrons and holes injected from the cathode and anode, respectively; subsequently, the bipolar current gradually reaches a steady state. Typical CGL materials contain n and p conductivity dopants used in the transport layer.

As previously disclosed, OVJP processes suitable for manufacturing OLED panels and similar devices involve dispensing OLED material in a heated gaseous mixture onto a recipient substrate via a printing nozzle (commonly defined as a Si die). The substrate is typically glass, but may be or comprise metal, plastic, or a combination thereof, or other materials. The substrate may comprise a pre-existing structure such as a passive or active matrix display backplane. The heated gas mixture is typically obtained by passing a carrier gas (e.g., H2, he, N2, or Ar) through a sublimation/evaporation source containing OLED material. OVJP differs from other deposition techniques such as vapor deposition, vacuum Thermal Evaporation (VTE), atomic Layer Deposition (ALD), etc., and deposition systems commonly known for those techniques are not suitable and cannot be readily adapted to OVJP techniques and materials. For example, ALD requires at least two separate precursors, each of which forms a self-limiting monolayer on the substrate surface. The precursors are alternately delivered to the substrate, and after exposure to the precursor pairs, an atomic layer is formed on the surface. In contrast, OVJP is a condensation process in which gaseous organic material condenses on a relatively cooler substrate. As another example, OVJP uses not only relatively high temperatures to sublimate/evaporate and transport organic materials to be deposited on a substrate, but also relatively cooler substrates to prevent damage to the organic materials deposited on the substrate. The temperature of OVJP organic sublimating sources is typically in the range of 200 ℃ to 450 ℃, which is much higher than the range used for Chemical Vapor Deposition (CVD) and similar techniques. CVD also uses substrate temperatures significantly higher than the source material temperature to allow the desired chemical reactions to occur on the substrate surface. OVJP also uses very small nozzle widths and relatively small nozzle-to-substrate spacings in OVJP depositors, both of which contribute to the precision deposition profiles achievable by OVJP, which are generally not achievable by other spray or nozzle-based deposition techniques. Furthermore, OVJP allows extremely accurate deposition of materials and is not typically used for large scale blanket deposition, as compared to blanket deposition techniques. OVJP processes typically use pressures between 10 torr and 1 atm (760 torr). The material source may be disposed within or outside the vacuum chamber.

The OVJP system includes one or more OVJP printheads that transfer hot gases containing organic materials to be deposited on a substrate to discrete locations (e.g., pixel or sub-pixel areas) on the substrate via one or more nozzles incorporated into the heads. The substrate typically contains pre-existing structures such as passive or active matrix backplane assemblies. OVJP systems typically include a number of OVJP printing nozzles, which are typically arranged in a pattern matching the pattern of the display backplane. In practice this means that the nozzle arrangement has the same pitch as the pixels on the resulting display. The nozzles may be provided by, for example, a series of channels through the printed die, each of which terminates in an orifice that ejects material during operation. "print die" as described herein refers to a component that includes deposition and exhaust channels that terminate in orifices that define nozzles. The printed die is typically fabricated using MEMS processes, but other techniques may be used, such as additive manufacturing, laser drilling or ablation, and the like. The nozzles are integrated into an assembly called a "print head" that includes gas distribution from the source to the die and manifold, a flight control mechanism that maintains the print die at a constant gap relative to the substrate as the print die move relative to each other, and in some embodiments, the components cool. The OVJP printhead may include one or more print dies. The OVJP printhead may also include a print manifold that distributes material into various channels in the print die and ultimately to nozzles located on the bottom side (i.e., the side facing the substrate) of the print die and printhead. The print manifold is typically a block of material (e.g., metal or silicon) that is attached to the print die. The manifold may also connect the print die to the printhead assembly. OVJP print engines typically include print dies, gas delivery manifolds and associated gas lines, z-positioning or fly-height adjustment systems, and in some cases, material-sublimating sources, such as sources for producing OLED material to be deposited on a substrate. Some arrangements disclosed herein use an integrated sublimating source as described in further detail below. Similarly, a "print bar" may include multiple printheads or print engines. During operation, embodiments disclosed herein may allow for independent adjustment of the positioning of individual print bars, print engines, and/or printheads, as described and illustrated in the various embodiments. In general, the same arrangement may be used with print engines having additional components with the print head in a single controllable unit when the arrangement disclosed herein refers to the arrangement or movement of the print head unless it is not possible based on the particular arrangement. In some embodiments disclosed herein, the positioning of the printheads on a common print bar may be controlled as a unit via the positioning of the print bar; alternatively or additionally, the position of each print head may be controlled independently of other print heads on the same rod and/or other print heads in the system.

In OVJP systems, it is often necessary to transfer and distribute the heated gas and organic material mixture hermetically from the system gas line connected to the organic vapor source, respectively, to the system gas line connected to the exhaust assembly. Thus, the print manifold in each print head can be used to direct gas from the inlet to the print die and from the print die to the outlet. It is also desirable to maintain the gas temperature within an appropriate range to prevent condensation (at low temperatures) or decomposition (at higher temperatures) and to protect sensitive system components and substrates from the heat generated in the printhead manifold. Typical transfer lines and exhaust lines used in OVJP and embodiments disclosed herein operate at temperatures of 250 ℃ to 450 ℃. The operating temperature range is selected due to the nature of the materials commonly used in the different layers of the OLED device, and may vary for the color of the deposited emitter. Preferably, for any particular material, the transfer line and the exhaust line operate at the same temperature or within 0 ℃ to 10 ℃ of each other. The transport gas used to transport the material for deposition is preferably maintained at the same temperature. A temperature gradient may be imposed between the material source and the printed die to prevent condensation, with the end of the source path varying about 10 ℃ to 20 ℃, with the printed die at the higher temperature end of the gradient.

It is also desirable to maintain the printed die within a vertical distance ("fly height") of the substrate that corresponds to the desired process conditions. OVJP fly heights are typically in the range of 20 μm to 60 μm. In some arrangements, a closed loop system using a distance sensor and vertical actuators on each print head may be used to maintain a desired fly height above the substrate.

Embodiments disclosed herein provide an OVJP system that includes a directly heated delivery line to provide a gas and organic material mixture to a print die, which can increase efficiency and reduce complexity of the system while still maintaining acceptable throughput, deposition quality and uniformity, and convenience.

Fig. 3 shows an example OVJP system as disclosed herein. The system includes a printed die 305 that ejects a carrier gas that transports organic material to be deposited on the substrate 300 toward the substrate 300. As used herein, a substrate may be described as being disposed "under" an OVJP print die or printhead if the substrate is disposed in the jet path of material ejected from the OVJP print die, regardless of its orientation with respect to each other with respect to the direction of gravity. That is, the print die may eject material in an upward direction, and the substrate may be disposed "above" the "print head" with respect to the direction of gravity. In this arrangement, the substrate is still considered to be disposed "under" the OVJP printed die as described herein.

One or more transfer lines 310 provide a carrier gas flow in which organic material to be deposited on the substrate 300 is entrained. A transfer line provides a flow of organic material from one or more material sources to OVJP print die 305, typically through print manifold 302. The transfer line 310 may be heated directly. As used herein, a directly heated line or "directly heated" component is a line or component that is configured to itself generate heat in some way, rather than heating by using a separately attached heater or a heater placed in close proximity as is used in some conventional OVJP systems. For example, as disclosed herein, a "directly heated" pipeline includes an arrangement in which the pipeline includes a resistive material that generates heat when an electrical current is applied to the material, thereby causing the pipeline itself to generate heat.

Fig. 4A shows an example of a directly heated delivery line according to embodiments disclosed herein. Fig. 4B shows an enlarged view of the proximal ends of the print manifold, print head and transfer line 310. The transfer line 310 may be formed of a resistive material as disclosed herein and connected to the electrical connections 401, 402 to form an electrical circuit that includes the resistive material of the transfer line 310. When an electric current is applied to the resistive material of the transfer line, it raises the temperature of the resistive material and thereby heats the material and the interior of the transfer line. The electrical return 310' may be used to complete an electrical circuit. The transfer line 310 may be made entirely or substantially entirely of electrically resistive material (i.e., with only a minimal or minimal amount of other material that does not significantly affect the electrical and/or heating properties of the line).

As shown in fig. 4B, the transfer line 310 and any return lines 310 'may be electrically insulated from the print manifold 302 and/or print die 305, such as by ceramic insulators 421, 422 or other connectors that provide a hermetic seal between the ends of the transfer lines 310/310' and the manifold 302. In this arrangement, the transfer line 310 itself is a heating element. A temperature sensor (e.g., thermocouple, RTD, etc.) may be attached to transfer line 310 for closed loop temperature control, such as via control line 317 as shown in fig. 3. Control line 317 may be connected to the processor to allow closed loop control of the transfer line temperature based on signals received from the temperature sensor. For example, signals from the temperature sensor may be provided to a processor, which in turn sends control signals to the transfer lines and/or exhaust lines, either directly or via other control components, to adjust the temperature of those lines, such as by increasing or decreasing the current applied to the resistive material of the lines.

In some configurations, the exhaust line 320 may also be a directly heated line. The same materials, configurations, and connections may be used as described with respect to transfer line 310. In particular, the exhaust line 320 may be directly heated by applying an electrical current to the resistive material forming the exhaust line 320 in order to heat the line and the interior of the line in the same manner as described above with respect to the transfer line 310.

Fig. 4C shows an example of a transfer line, exhaust line, and printhead including various insulating structures. To maintain the desired temperatures of the transfer line 310 and exhaust line 320 and to prevent heat generated by these components, they may be surrounded by heat shields 455, 456, respectively, as shown. The heat shields 455, 456 may be external conduits having uniform cross-sectional shapes and areas. Because heat generation is essentially uniform in constant cross-section tubes such as transfer line 310 and exhaust line 320, heat loss along the length of the tube should also be uniform due to temperature uniformity of the gas path. To achieve this, it may be necessary to ensure a laminar flow of ambient gas along the tube, which in turn provides a low and constant convection loss from the heating tube element. One way to achieve this is to use constant cross-section tubing 455, 456 as shown in fig. 4C that matches and follows the shape of the transfer line 310 or exhaust line 320. The shape of the cross-section of this conduit may be adjusted as necessary to promote temperature uniformity or a desired gradient along the gas path. The outer conduit may be circular as shown in fig. 4C or rectangular as shown in fig. 4D. The constant cross-sectional mask may or may not be forcibly cooled, as needed to maintain temperature uniformity, as well as to maintain the temperature of other critical elements of the print engine below a desired level, as described in further detail below. Where a non-cooled cover is used, it may preferably be constructed of a thin-walled material having high thermal conductivity and low emissivity to improve infrared heat reflection.

The slip joints 460 or other structures in the heat shields 455, 456 may be used to allow sufficient clearance to accommodate displacement due to thermal expansion and/or vertical movement of the printheads during operation. Fig. 4D shows another example of a heat shield 455 in the form of a tube disposed about a transfer line 310, where the transfer line 310 is arranged in an S-shape, as described in further detail below. As previously disclosed, similar structures may be used around the exhaust line 320 and/or other gas delivery lines in the system. Also shown in fig. 4C is a cold plate or other active cooling device 433 that can be used to reduce heat transfer between the printed die/manifold structure and the substrate. For example, the active cooling device 433 may be a water chiller having a supply and return line 434, the supply and return line 434 providing for circulation of water or similar coolant through the device. The use of the active cooling device 433 may reduce or prevent damage to materials that have been deposited on the substrate during operation of the OVJP system.

Alternatively, the heat shields 455/456 may be in the form of insulating housings, as shown in fig. 4E, which also shows the transfer line 310 in an S-shaped arrangement. The housing 455 may be, for example, a container with a sealable lid 455', such as a ceramic housing.

Regardless of the particular form, the heat shields 455, 456 may have sufficient clearance to allow movement between a maximum horizontal displacement and a minimum horizontal displacement during operation of the OVJP system. The heat shields 455, 456 may also contain structure such as the slip joint 460 previously described with respect to fig. 4C to allow for thermal expansion and contraction and/or vertical movement of the OVJP printhead relative to an external source that is not integral to the printhead.

Instead of using directly heated lines, indirect heating sources may be used to heat transfer line 310 and/or exhaust line 320. In this configuration, the relevant tube portion is surrounded by a heated housing (i.e., a small oven). The housing may be made of a material having a high thermal conductivity (e.g., copper, molybdenum, etc.) to improve thermal uniformity. A plurality of discrete heater elements are attached to the body of this housing at strategic locations. Temperature control is facilitated by sensors embedded within the heater element, or alternatively, by sensors attached to corresponding locations on the gas conducting tube. When copper or similar materials are used, the surface of the tube may be coated with Ni or similar materials to reduce emissivity and reduce energy loss through radiation.

Regardless of the particular arrangement used to heat the gas channels and print die, other elements of the printhead (e.g., voice coil actuator, fly-height sensor, etc.), as well as the substrate, may need to be protected from overheating. One or more water cooling hoods or other active cooling elements may be used to provide this cooling. The cover forms a second layer of housing around the heated portion of the printhead, or a plurality of housings as appropriate, for example, as shown at 433 in fig. 4C.

Further, the print manifold may be mounted to the mounting plate by a flexure. The upper heat shield may help maintain the mounting plate at room temperature when the manifold is heated to an operating temperature. Manifold deformation caused by printhead heating is managed by constraining the manifold only in the vertical direction while leaving it free to expand laterally, and using a correctly stiff flexure (determined by FEA analysis) by limiting the stress caused by length changes caused by manifold temperature changes.

Equally stiff flexures positioned equidistant from the (longitudinal) center of the mounting plate may be used so that the midpoint of the manifold relative to the mounting plate (the thermal center) does not change with increasing manifold temperature, i.e., the deformations are symmetrical about the thermal center. The flexure may further ensure that forces on the manifold block remain minimal, which in turn minimizes out-of-plane deformation.

The preferred material for the flexure has low thermal expansion and should be compatible with OVJP process temperatures. For example, grade 5 Ti or some stainless steel alloy may be used.

The heat shield itself may be made of a metal having a high thermal conductivity (e.g., copper or molybdenum). The micro-channels within the material may be hermetically sealed by suitable means, such as brazing, welding, diffusion bonding, etc. The surface of the cap may be plated with an chemically inert metal having a low emissivity. In the case of water cooling, water may be pushed through the passages of the heat shield by a pressure differential. The temperature of the incoming water can be controlled by an external cooler, while the temperature of the outgoing water can be monitored and regulated by adjusting the pressure differential as desired.

Returning to fig. 3, a print manifold 302 provides an organic gas delivery line 310 and an exhaust line 320 and incorporates printed die305, and an interface between the printing nozzles in 305. Typically, OVJP print die 305 includes a series of through holes connected to the print nozzles, the through holes organized in at least 2 groups corresponding to the organic gas supply and discharge. Typical printed die sizes range from 30mm to 100mm, but the nozzle occupies only a portion of this length. For example, the orifices constituting the nozzles in the print die 305 may occupy a central portion extending across 76mm of the 100mm print die. Manifold 302 may be formed of multiple layers and contain channel structures to distribute the organic gas evenly to the transport through holes and from the exhaust through holes, with the gas flow into and out of the die meeting the requirements of the target printing process, and without "dead spaces" that may trap the gas, resulting in unintended condensation. Depending on the die design, the transport and exhaust channels may be defined on the same side or opposite sides of the die. Examples of suitable printed die arrangements, fabrication techniques, and the like are provided in U.S. patent nos. 9,583,707, 10,704,144, 11,104,988, 11,220,737, 11,267,012, and 11,588,140, the contents of each of which are incorporated by reference herein in their entirety, and U.S. patent publication No. 2021/0280785, the contents of which are incorporated by reference herein in their entirety. Illustrative examples of print die arrangements that may be particularly suitable for use in connection with the embodiments disclosed herein are described and shown in fig. 4 and related text of U.S. patent No. 11,267,012, and fig. 5-6 and related text of U.S. patent No. 10,704,144, although other arrangements may be used. For example, fig. 4 of U.S. patent No. 11,267,012 shows a cross-sectional view of a nozzle assembly 400, the nozzle assembly 400 having a transport channel adjacent to or surrounded by one or more exhaust channels 402. A transport gas transporting the material to be deposited is ejected from the orifice of the transport channel 401. Material 305 not deposited on the substrate is removed through the exhaust channel 402. The confining gas 403 may be provided from a source (e.g., nozzle, ambient source, etc.), from a location below the nozzle and adjacent to the nozzle and/or the exhaust channel 402 in a direction opposite to the flow of material ejected from the orifice of the delivery channel of the nozzle. Restricting the gas from flowing from outside the deposition zone and removing the remaining material The material is directed into the exhaust channel 402. The exhaust passage 402 is typically connected to a vacuum source. The exhaust channel 402 may be angled relative to the transport channel 401 to improve the uniformity of the deposited material on the substrate in a defined region of the deposited material. The exhaust channel 402 may partially or completely surround the transport channel 401. In some configurations, the nozzle orifice may be defined by a flat edge of the nozzle block and a channel within the nozzle block such that no additional tapered or extended physical portion beyond the lower surface of the nozzle block is required. The nozzle orifices may be bifurcated or otherwise divided, for example, by a feed channel separator 404. As another example, fig. 5-6 of U.S. patent No. 10,704,144 show views of "DEC" type print dies ("nozzle blocks") that use one or more streams of shielding gas around a micro-nozzle array. The ambient gas in an OVJP deposition chamber is typically relatively stagnant. The flowing shielding gas may use a purified shielding gas such that water and O in the deposition chamber ₂ The content is less than 0.001ppm. In this arrangement, a shielding gas channel 501 mounted in front of and/or behind the deposition nozzle creates a flow of purge gas that isolates the nozzle array from residual gases that may be present in the chamber. The shielding gas channels 502 installed between the nozzle arrays provide a confining gas source to achieve accurate patterning and prevent vapor from adjacent arrays from diffusing together. Fig. 6 of us patent No. 10,704,144 shows a view of a printed die from the substrate normal direction in fig. 6. The depositor contains a single orifice or multiple orifices at the end of the passage inside the monolithic nozzle block. The delivery orifice 603 delivers a mixture of one or more organic vapors entrained within an inert delivery gas. The exhaust port 604 communicates with an exhaust channel that withdraws gas from the region between the depositor and the substrate. The optional restriction channel 605 is formed by a depression in the surface of the depositor. These channels provide a low resistance path for the confining gas flowing from the edge of the nozzle block to the centerline of the depositor where it is desirable to block organic vapor diffusion. The confining flow in this arrangement is supplied by the gaseous environment surrounding the depositor, as opposed to the chamber environment, which is from the shielding gas flow. Alternatively, the confinement gas may be supplied via one or more of the confinement apertures 606.

The manifold should be made of a material that can withstand the temperatures used in OVJP, preferably a material that is resistant to temperatures of 500 ℃ or higher to be compatible with a wide range of OLED materials. The manifold material should also be a good thermal conductor. The manifold typically incorporates a heater for maintaining the organic material in the transport gas at a temperature sufficient to prevent condensation but not so high as to damage the organic material. The material should also have a relatively low coefficient of thermal expansion, preferably matching or approaching that of the printed die material. The material should also be easy to manufacture for the transport channels, the vent channels and any other channels, for example via micro-machining, photolithographic techniques, 3D printing or other methods.

Based on these requirements and because OVJP printed dies are typically made of Si, suitable materials for the manifold include metals such as W and Mo, ceramics such as AlN and single crystal or poly/columnar Si.

The printed die is assembled with the print manifold in a gas tight manner, i.e., to minimize the amount of gas that can escape through the interface between the two. This in turn minimizes the risk of uncontrolled deposition on the substrate and the risk of particle generation caused by condensation at the leak location. As previously disclosed, the material stream used in the OVJP deposition process comprises an organic material sublimated into a carrier gas stream. The carrier gas is typically a low molecular weight compound such as H or He, so it is convenient to express the gas tightness requirement in terms of the He leak rate. Preferably, the leakage rate of the print manifold/die assembly is about 1x10 ^-7 To L/s, preferably maintained throughout the OVJP operating temperature range up to 500℃, and for a duration conducive to uninterrupted system operation, which may be on the order of several months.

Suitable techniques for joining the manifold and the printed die include mechanical clamping, such as applied with uniform force via appropriately distributed and preloaded bolts, the use of belleville springs to apply the preload when the printhead is temperature cycled, and sealing, such as using c-rings, au wires, and the like. The bolts and springs used in the attachment should be compatible with the OVJP process temperature, so materials such as Nitronic 60 and 718Nickel can be used. Other bonding techniques may be used, such as high temperature soldering (e.g., auIn), brazing (e.g., intag), diffusion bonding (e.g., ag), glass frit bonding (using paste, preform, or tape), or fusion bonding (for Si manifold/die).

Minimizing stresses and deformations in the assembly is also beneficial because these can lead to leakage and reliability problems, particularly for joining methods, which involve temperatures far exceeding the highest process temperature. The introduction of some compliance in the tie film, for example by using a thick ductile film such as Ag, can help alleviate such problems. Preventing silicide formation, which may weaken the die interface, may be accomplished using a barrier layer (e.g., ni).

Just as the manifold connects the supply gas and exhaust gas to the nozzles of the die, the manifold connects to the system-level gas distribution infrastructure. This connection may be direct or involve an intermediate manifold (e.g., at the print head level of a multi-die print head, or at the print bar level, which refers to a subsystem made up of multiple print heads mounted on a common mount). Since each print head can be moved independently in the vertical direction for flight control and start-stop (lift and landing) of printing, the gas connection method should facilitate a gas tight but geometrically flexible interface. In addition, this interface should maintain the transport gas and exhaust gas at the desired elevated temperatures.

Arrangements commonly known in OVJP technology for providing the required flexibility, such as bellows, may exhibit significantly increased cross-sections and undesirable characteristics of possible gas stagnation areas. These characteristics may promote the agglomeration and accumulation of organic deposition chemicals. To mitigate these effects, it may be preferable to maintain the transfer line and exhaust line at constant cross-sections as previously disclosed, with the cross-sectional area selected to be only as large as necessary for the desired conduction. Various flexible pipe elements may be used to achieve these desired effects. The ends of the flexible element should terminate in flanges for sealing the gas connection with the manifold and the print bar of the print head, respectively. To accommodate the high temperatures, various types of metal seals may be used. One of which may be a soft metal (e.g., gold) wire loop and the other may be a C-shaped seal made of stainless steel or superalloy.

One suitable arrangement is to use a three-dimensional helical portion of tubing in the transfer line, for example, as shown in fig. 5. Another variation is an S-shape formed by a constant cross-section tube, as shown in fig. 4D, 4E and 6. Another variation is to use an L-shaped bend in the tube that is of sufficient length in the horizontal leg to provide the desired compliance, for example, as shown in fig. 4A and 4C.

In order to keep the tube as flexible as possible, it may be preferable to use a minimum conduction-defined cross section of the tube with the thinnest wall. Because the exhaust side conduction should accommodate higher flow than the delivery side, multiple tubes may be used, as shown in fig. 6.

The process gas flowing through the print head to the nozzles, and the exhaust gas when evacuated through the print head, should be maintained at a relatively high process temperature. The process window is relatively narrow: too high a temperature results in decomposition of the organic matter, while too low a temperature results in condensation of the precursor on the gas channel walls. Because the process flow rate is relatively small, the heat capacity of the process gas, and even the heat capacity of the exhaust gas, is not sufficient to maintain the desired temperature of the channels. For this reason, the gas conduit is preferably heated using an external energy source or a direct heating arrangement as previously disclosed. Furthermore, when the organic gas passes through the printed die itself, the temperature of the organic gas must be maintained within a well-defined temperature range. On the one hand, condensation must be avoided; this is achieved by ensuring that the gas undergoes a relatively small temperature gradient when delivered to the printing nozzle. On the other hand, too high a temperature may lead to dissociation of the organic material. Thus, a print head may be required and have controllable heating capabilities. For example, referring again to fig. 3, heating elements may be clamped or otherwise bonded to both sides of the manifold 302 and across its width and height, thereby providing adequate and uniform thermal contact. As another example, the heater trace may be embedded directly in the manifold, which may be implemented with ceramic materials such as AlN, al2O3, and Si3N 4. The W-traces may be screen printed between the various layers that make up the manifold structure and sintered during the AlN firing process. The heater traces may also be patterned directly onto the manifold, for example via screen printing or photolithographic techniques. This arrangement may be particularly suitable for Si-based manifolds.

Thermal modeling can be used to verify that the heater configuration/trace layout maintains the gas within the correct temperature range as it passes through the printhead. To achieve this, the heater may need to be subdivided into a plurality of zones, which may be independently controlled or have a static relationship to each other. For real-time closed loop control, a temperature sensor such as a thermocouple or Resistance Temperature Detector (RTD) may be incorporated into the printhead. In the case of an AlN manifold, WRTD may be embedded in a similar manner as the heater traces. RTD traces can also be patterned on Si manifolds in the same manner as heater traces.

Referring again to fig. 3, the print head flying height h, i.e., the gap between the printed die and the substrate (across the entire die), is an important parameter in determining the thickness and uniformity of the printed line. OVJP printheads as disclosed herein may incorporate a flight control mechanism to maintain this gap at a desired value as the substrate is scanned thereunder. In general, the flight control mechanism can include actuation elements and gap sensor elements on either side of the printed die. These can operate in closed loops with each other: the sensor measures the fly height and the actuator adjusts the height to bring the fly height to a target value. Closed loop control of fly-height may be achieved by various algorithms (e.g., proportional-integral-derivative or limit-based control) resident on and executed by a PLC, motion controller, or other suitable processor. Such an algorithm may control the position of the voice coil in real time based on the readings (changes) of the fly-height sensor via a servo driver connected to the PLC/motion controller.

Typical operating ranges for the flight control mechanism in an OVJP system are:

altitude range: 20-60um

Fly height sensing resolution: <100nm

Flight control error: +/-0.5um (avoiding significant non-uniformity of display quality)

Control bandwidth-10 Hz (following glass contour changes)

Insensitive to substrate surface properties (reflectivity, conductivity)

The flight control mechanism should also be able to lift the print head to or from a so-called lift gap, which is the fly height at which no deposition occurs. In OVJP, the lift gap is typically about 200 μm. The landing and lifting should occur as a narrow stripe at the front and rear edges of each panel row, typically leaving less than about 5ms for movement as the substrate moves.

Vertical actuators suitable for use with the OVJP systems disclosed herein include voice coils, piezoelectric motors, linear motors, pneumatic actuators, and the like. A pair of actuators may be connected to the parallel arm links to form a vertical motion mechanism. The pivot of each link is a self-contained flexure-type bearing that utilizes an internal flat cross spring within the cylinder. The two actuators are positioned side by side, allowing tilting action of the print head about the centre line. The bearings of the motion mechanism are flexure-based and thus have a spring rate that allows some movement in the radial and axial directions. This compliance allows for a minimum amount of rotation of the print head by varying the force of each voice coil. An adjustable spring balance can be used to counteract the vertical force from gravity, which allows minimizing the size of the actuators, as they only need to take into account the forces due to acceleration. The printhead module can be mounted to the mounting plate by three actuators, allowing for mounting and leveling.

Fly-height sensors suitable for use with the OVJP systems disclosed herein include optical sensors (such as spectral interference, chromatic confocal, and triangulation sensors), electrical sensors (such as capacitive and eddy current sensors), and pressure sensors (although these sensors may be too sensitive to surface conductivity). In addition, an absolute linear encoder connected to the moving part of the voice coil may serve as a reference and tracking sensor for the printed position. It may also provide redundancy for the fly-height sensor and, due to its generally larger extent, it may be used to control larger vertical movements, such as lifting required to stop deposition.

The print head may be mounted as a unit to the bottom of the voice coil moving plate. In this arrangement, exchanging the head requires only 4 bolts and untangling the gas lines from the head, which allows different head designs to be interchanged.

An important aspect of accurate gap sensing is the calibration of the fly-height sensor. There are several ways in which this can be accomplished, including touch and non-touch methods.

The touch method involves placing the edge of the printed die on an ultra-flat reference surface (e.g., gauge block). Thus, the "active area" of the die defining the nozzle is not in contact with the block. The reference surface may be made coplanar by mounting the reference surface on a flat substrate (e.g., a granite slab). A calibrated shim or other similar structure may be used to position the fly-height sensor to the correct distance from the reference surface, after which the fly-height sensor itself may be used to measure the distance from the sensor to the reference surface on both sides, i.e., the vertical offset between the sensor and the die, to achieve sensor calibration. The use of a reference surface made of a low thermal conductivity and low thermal expansion material (e.g., quartz, ceramic) allows calibration to be performed at the print head operating temperature without damaging the fly height sensor (assuming the heat shield is in place). The non-touch approach may use a separate sensor, such as a laser distance (triangulation) sensor that moves along the length of the die on a platform with low flatness (vertical position error). This sensor can be used to measure the vertical offset between the FH sensor and the corresponding die edge without requiring contact with the die. This configuration also allows for calibration of the thermal print head.

The default OVJP printhead configuration may include a single die and a pair of fly-height sensors and vertical actuators, as previously disclosed. For systems capable of processing relatively large glass substrates, such an arrangement may result in significant system cost and complexity. For example, a 55 "panel layout on a Gen 8.5 substrate would require 32 single die printheads (with 64 fly height sensors and 64 vertical actuators) for each printed material. In general, OLED TV fabrication will require printing a different emissive layer for each color (red, green, and blue), so this will involve a total of 96 printheads and 192 sensors/actuators.

One way to simplify the complexity and cost of system control is to use common fly height control for multiple printed dies. For example, a printhead combining 4 dies may be significant for the 55"gen 8.5 layout discussed above; this would involve 24 printheads with 48 fly-height sensors and vertical actuators (the latter of which would need to be increased in size relative to a single die printhead to match the mass increase). This configuration no longer provides individual control of the fly height and tilt of each die, and thus it is important to ensure that the dies in such printheads are accurately aligned with each other in the vertical direction (additionally, glass flatness would need to be controlled over a large distance). The maximum allowable vertical alignment error between dies in a multi-die printhead is +/-0.35um.

Theoretically, this level of accuracy can be achieved by adjusting the die to an ultra-flat reference surface. In practice, however, it is often preferable to avoid contacting the surface of the die in which the nozzles are defined to prevent contamination and damage. This can be achieved by measuring the vertical distance between the die (edge) and the planar reference plane and adjusting this distance until all die edges are within the error tolerance. One way to measure the distance between the die edge and the planar reference plane is by using a method similar to non-contact sensor calibration, i.e. using a laser distance sensor that can be moved along the length of the printed die on a platform with ultra-low flatness, itself mounted on an ultra-flat surface (e.g. granite). The error in the distance measurement must be significantly less than the allowed vertical alignment error between the dies, e.g., 0.1 μm or less. Additionally, a platform flatness level compatible with allowed die alignment errors may be achieved by implementing active compensation based on flatness metrology. This requires precise movement of the laser distance sensor in the vertical direction, which can be achieved by means of, for example, a piezo-electric drive or a linear motor.

The adjustment of the position and tilt of the individual dies in the multi-die printhead should be based on the measured distance values. The scalability requirements are also significantly less than the resolution of the allowed vertical alignment errors (e.g., 0.1 μm or less) between die. Suitable options for use with the OVJP systems disclosed herein include lockable ultrafine pitch adjustment screws (for manual adjustment) or automatic adjustment using, for example, a piezoelectric drive or linear motor. The latter increases system complexity but would allow for closed loop alignment using input from the laser distance sensor, resulting in faster resource less sensitive procedures. The multi-die printheads used in the systems disclosed herein may still involve separate manifolds for each die, especially in configurations where a common manifold would be more difficult to manufacture.

It should be understood that the various embodiments described herein are by way of example only and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without departing from the spirit of the invention. The invention as claimed may thus comprise variations of the specific examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It should be understood that the various theories as to why the present invention works are not intended to be limiting.

Claims

1. An organic vapor jet printing OVJP apparatus, comprising:

an OVJP print die comprising one or more transport channels to transport organic material and carrier gas to an area under the print die;

a directly heated transfer line connected to the one or more transfer channels and configured to be connected to the

A source of the organic material external to an OVJP printed die, the directly heated transfer line comprising:

a resistive material; a kind of electronic device with high-pressure air-conditioning system

A plurality of electrical connections to the resistive material;

wherein when an electrical current is applied to the resistive material via the plurality of electrical connections, the resistive material heats the interior of the directly heated transfer line.

2. The OVJP apparatus according to claim 1, wherein the directly heated transfer line has a constant cross-sectional shape and area.

3. The OVJP device according to claim 1, wherein the directly heated transfer line is formed entirely or substantially entirely of the resistive material.

4. The OVJP device according to claim 1, wherein an end of the directly heated transfer line connected to an OVJP printed die line is electrically insulated from the OVJP printed die.

5. The OVJP apparatus according to claim 1, wherein the directly heated delivery tube forms a spiral, S-shape or L-shape.

6. The OVJP device according to claim 1, further comprising:

one or more temperature sensors; a kind of electronic device with high-pressure air-conditioning system

A processor in signal communication with the one or more temperature sensors and configured to perform closed loop control of temperature within the directly heated transfer line based on temperature signals provided by the one or more temperature sensors.

7. The OVJP device according to claim 1, further comprising a heat shield disposed around the directly heated transfer line.

8. The OVJP device according to claim 7, wherein said heat shield comprises a ceramic housing having sufficient clearance to allow movement of said directly heated transfer line when said OVJP device moves between a maximum horizontal displacement and a minimum horizontal displacement.

9. The OVJP apparatus according to claim 7, wherein the heat shield comprises a tube disposed around the directly heated transfer line, the tube having a constant cross-sectional shape and area.

10. The OVJP device according to claim 9, further comprising an active cooler arranged and configured to cool at least a portion of the conduit.

11. The OVJP device according to claim 1, further comprising:

A directly heated exhaust line connected to one or more exhaust channels in the printed die to remove material from under the printed die and configured to be connected to an external source of vacuum, the directly heated exhaust line comprising:

A plurality of electrical connections to the resistive material;

wherein the resistive material of the directly heated exhaust line heats an interior of the directly heated exhaust line when an electrical current is applied to the resistive material of the directly heated exhaust line via the plurality of electrical connections of the directly heated exhaust line.

12. The OVJP apparatus according to claim 11, wherein the directly heated exhaust line is disposed within a heat shield conduit having a constant cross-sectional shape and area.

13. The OVJP device according to claim 12, further comprising an active cooler arranged and configured to cool at least a portion of the conduit.

14. The OVJP device of claim 1, further comprising a manifold configured to distribute material from a flexible conduit to the one or more delivery channels.

15. The OVJP device according to claim 14, wherein said manifold comprises one or more materials selected from the group consisting of: w, mo single crystal Si, polycrystalline Si, columnar Si, alN, al ₂ O ₃ 、Si ₃ N ₄ Or a combination thereof.